Geared more for the professional, this site has over 36,000 searchable public record databases. It very easy to get lost on this site because it has so much to offer. Free and premium databases are clearly marked.http://www.searchsystems.net/

Initially sorted by State, then jump to the specific county where you believe the business you're looking for is located, and finally to the county recorder of that county to see if any fictituous business name statement has been filed for the company. The fictitious business name statement will have the company's address and most likely their phone number and contact person.http://dir.yahoo.com/Regional/U_S__States/

A small piece of free software that allows you access to satellite photos and overlays streets and landmarks on top. Great for verifying whether an address is an office building or a postal annex. Enter an address and seemingly fly to the location. DSL speed or better recommended.http://earth.google.com/